Why was Doflamingo sent to Impel Down

[ahill]

That doesn't make any sense. He even had the importance to summon up the CP0 and it was said that he still had the "strength" of a Tenryuubito because he had the knowledge of some treasure or something like this. Really bad write imo.

 

[SSJ2]

He was a criminal

 

[Yoshi]

He betrayed the World Government. Just like Crocodile did.

 

[Papasmurf]

His arc was a copypasta

 

[sei'taer]

The strawhats exposed what he was doing to the people of dressrosa in a very public way.

They really didn't have a choice.